Capper/decapper system and method

A system and method for gripping, torqueing and releasing an element so as to cap and/or decap a container, such as those typically utilized to house specimens in laboratory environments. The system is driven by a single bi-directional motor linked to a coupler assembly via a rotating threaded shaft. The coupler assembly is configured to engage with an element, such as a cap or container, via mechanically-biased splines that are actuated without any complex linkages, or operative connection to the motor or other powered components. The system employs an ejector nut and an ejector, both of which are concentrically positioned about the threaded shaft. The ejector nut translates along the shaft as a function of the shaft's rotation, so as to permit the retraction of the ejector when an element is engaged in the coupler assembly or cause the ejector to extend into the coupler assembly to disengage the element. The direction and rotation of the motor is controlled by a system coupled to sensors positioned within the system. Such control system may include one or more processors, component interfaces, and data storage/memory. The sensors may include multiple optical, magnetic or mechanical means for monitoring one or more of the positions of the ejector nut and ejector along the threaded shaft, and/or the rotational position of the coupler assembly.